Optimization of microstructural parameters for hard-soft nanocomposite permanent magnets
Abstract
We use finite temperature micromagnetic simulations to investigate hysteretic properties of hard/soft nanocomposite permanent magnets. Several generic geometries are considered including bilayers, superlatices, and different core-shell structures. We perform multiparameter optimization of the permanent magnet properties with respect to grain sizes, texture, and soft phase volume content. In addition, the effects of thermal fluctuations and the variation of the micromagnetic parameters at the hard/soft interface are studied. In particular, we find that the properties show typically only a small dependence on the interface exchange unless it becomes order of magnitude smaller than exchange in common 3d magnets in which case energy products and optimal soft phase content decrease dramatically. This behavior is, however, different for bilayer system with perpendicular anisotropy. Here we demonstrate that the competition between dipolar interactions and the interlayer exchange leads to significant dependence on the latter even for moderate exchange coupling strengths. Our results are compared with existing experimental data for Nd2Fe14B/Fe, SmCo5/Co, and MnBi/FeCo nanocomposites.
This work was supported by the project: ``Solid State Processing of Fully Dense Anisotropic Nanocomposite Magnets,'' ARPA-E Control Number 0670-4987. Ames Laboratory is operated by Iowa State University under Contract DE-AC02-07CH11358.- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2015
- Bibcode:
- 2015APS..MART30006W